Post-Traumatic Exostosis

Solitary osteochondromas are commonly thought of as neoplasms. But, there is a theory that they may be the result of injury, with experiments in rabbits showing osteochondroma formation following resection of the periosteum of the metaphysis or diaphysis.

A common location for avulsion injuries in children is at the apophyses, which can result in a prominent exostosis. The best known of these are seen with Osgood–Schlatter and Sinding-Larsen-Johansson diseases.

Apophyses in the pelvis can also be affected. The case above shows a post-traumatic exostosis at the anterior inferior iliac spine, the site of origin of the rectus femoris muscle.

References

• Goodwin MA. Myositis ossificans in the region of the hip-joint. Br J Surg. 1959 Mar;46(199):547-9.
• Hwang SK, Park BM. Induction of osteochondromas by periosteal resection. Orthopedics. 1991 Jul;14(7):809-12.
• Irving MH. Exostosis formation after traumatic avulsion of the anterior inferior iliac spine. Report of two cases. J Bone Joint Surg Br. 1964 Nov;46:720-2.
• Richardson RR. Variants of exostosis of the bone in children. Semin Roentgenol. 2005 Oct;40(4):380-90.